Conventional prior art mass market computing platforms include personal computers, server computers, information appliances, communication devices, display devices, hard copy devices, and the like.
There is substantial potential, at least in theory, for widespread interaction between such computing platforms. However, because of the potential for fraud and manipulation of electronic data, such interaction and, in particular, fully automated transactions between such computing platforms are often avoided. The fundamental issue is one of trust between interacting computer platforms.
There have been several prior art schemes which are aimed at increasing the security and trustworthiness of computing platforms. Predominantly, these rely upon adding in security features at the application level, as opposed to building them into the fundamental hardware components of the computing platform, and although such prior art schemes go some way to improving the security of computer platforms, the levels of security and trust gained thereby may be considered insufficient for some applications in which greater confidence in the trustworthiness of the underlying technology may be required.
In the applicant's co-pending disclosures ‘Trusted Computing Platform’, filed at the European Patent Office on Feb. 15, 1999, the entire contents of which are incorporated herein by reference, and ‘Computing Apparatus and Methods of Operating Computing Apparatus’, there is disclosed a concept of a ‘trusted computing platform’ comprising a computing platform which has a ‘trusted component’ in the form of a built-in hardware and software component. Two computing entities, each provisioned with such a trusted component, may interact with each other with a high degree of ‘trust’. That is to say, where the first and second computing entities interact with each other, the security of the transaction is enhanced compared to the case where no trusted component is present, because:                A user of a computing entity has higher confidence in the integrity and security of his/her own computer entity and in the integrity and security of the computer entity belonging to the other computing entity.        Each entity is confident that the other entity is in fact the entity which it purports to be.        Where one or both of the entities represent a party to a transaction, e.g. a data transfer transaction, because of the built-in trusted component, third party entities interacting with the entity have a high degree of confidence that the entity does in fact represent such a party.        The trusted component increases the inherent security of the entity itself, through verification and monitoring processes implemented by the trusted component.        The computer entity is more likely to behave in the way it is expected to behave.        
However, if a first computer platform user enters a geographical area, for example, a building, in which the computer platforms are unfamiliar to him/her, the security attributes of such computer platforms will also be unknown. Thus, the user will be unaware of the computer platforms available for use, and also the degree of confidence with which he/she may interact therewith.
Existing methods of providing or publishing security information include a “Public Key Infrastructure” and key distribution systems.
In a Public Key Infrastructure, a certificate states certain attributes of a target and is signed by some previously trusted entity. A visitor to, for example, a building, obtains a certificate and is able to verify the authenticity of the certificate because of prior knowledge of the trusted entity. The visitor trusts the trusted entity, and therefore trusts the attributes (including security attributes) stated in the certificate.
In known key distribution schemes, the visitor receives keys of a target from a key distribution service. The key distribution service is expected to trust the visitor, and vice versa. Keys may be expected to be trusted by the visitor because they are signed by the key distribution service, and the visitor is able to verify such signatures. Keys may be rendered confidential because of intimate contact with a node of the key distribution service. Alternatively, keys may be rendered confidential because they are encrypted by the key distribution service, and the visitor is able to decrypt such data.
Many geographical areas have a central information point from which general information may be obtained by a visitor who is unfamiliar with that area. However, such information is usually only displayed on a screen for perusal by the visitor. There is usually no way of saving such information electronically in a user's computer platform, for example, for reference or use later, and even if there were, it is unlikely that the user would trust the integrity and security of the information point sufficiently to allow it to interact with his/her computer platform.